APPARATUS AND METHOD FOR IMPLANTING COLLAPSIBLE/EXPANDABLE PROSTHETIC HEART VALVES
Apparatus for delivering a prosthetic heart valve into a patient by means that are less invasive than conventional open-chest, open-heart surgery. The prosthetic valve may be collapsed while in a delivery device. When the valve reaches the desired implant site in the patient, the valve can be released from the delivery device, which allows the valve to re-expand to the configuration in which it can function as a heart valve. For example, the delivery device may be constructed to facilitate delivery of the prosthetic valve into the patient via the apex of the patient's heart.
This application claims the benefit of U.S. provisional patent application 60/937,361, filed Jun. 26, 2007, which is hereby incorporated by reference herein in its entirety.BACKGROUND OF THE INVENTION
This invention relates to collapsible/expandable prosthetic heart valve delivery systems which can house, retain, maintain, transport, deploy, help anchor, and release (and, if necessary, reposition and/or retrieve) a collapsible prosthetic heart valve via a minimally invasive (or at least reduced invasiveness) port access, e.g., at the apex of a patient's heart and through the intercostal space of the patient's ribs.
The field of collapsible/expandable prosthetic heart valves is relatively new. The general idea is to provide a prosthetic heart valve that can be collapsed to a relatively small size (diameter) for delivery into the patient with reduced invasiveness to the patient's body (typically via a tube of relatively small diameter). When the valve reaches the desired implant site in the patient, the valve is released from the delivery apparatus and expanded to its full operating size. This also includes securing the valve to tissue of the patient at the implant site.
There are several approaches to delivering and deploying such collapsible/expandable prosthetic heart valves using arterial or venous systems of the patient. However, these approaches may impose certain constraints, such as requiring smaller delivery system profiles (cross sections) so that they can be used in diseased and smaller vessels and to minimize emboli risk. This may result in undesirable trade-offs in valve design and performance in order to accommodate the demand for delivery of the valve through smaller delivery system profiles.
Ideally, the delivery system should be designed around a durable and efficient valve design, thus not compromising any of the valve's long-term implant performance requirements. In doing so, the valve design should be adequate for its intended performance and long-term durability functions. This may result in valve profiles in the collapsed state that are somewhat larger than would be appropriate for human artery or vein delivery approaches, thereby calling for an alternative route to delivering the valve to its intended implant site.
The transseptal (through the septum of the heart) antegrade (delivery in the same direction as native blood flow) approach is one approach that has been tried. In the transseptal approach, access is gained through the venous circulatory system leading to the right atrium. A puncture is made through the septum wall separating the left and right atria (hence the term transseptal). The catheter is then advanced through the mitral valve into the left ventricle and looped back up ending at the aortic valve. This approach may have some disadvantages, however. For example, it may result in damage to the mitral valve and the associated chordae when trying to gain access to the aortic valve. In contrast, the transapical (through the apex of the heart) antegrade approach may offer a better and safer alternative for entering the left ventricle (“LV”) for direct access to the aortic and mitral valves. (See, for example, P. Tozzi et al., “Endoscopic off-pump aortic valve replacement: does the pericardial cuff improve the sutureless closure of left ventricular access?”, European Journal of Cardio-thoracic Surgery 31 (2007) 22-25, available online 6 Sep. 2006.) Accessing the LV through a small port at the apex (lower end) of the heart is not new, as this has been the practice for several decades in placing bypass shunts in pediatrics. There are good, long-term, clinical experiences with this access approach to render it safe and effective. With an optimum delivery system design, safer and more effective direct access to the aortic or mitral valve can be achieved for the purposes of repair and/or replacement of defective native valves.SUMMARY OF THE INVENTION
The delivery system of the present invention may comprise several components working together to facilitate various functions required for delivery and deployment of a collapsible/expandable prosthetic heart valve. The delivery system may include an elongated shaft attached to an ergonomic handle. The handle may incorporate several controls for several functional features within the device. One of these controls may be a rotating wheel that functions to advance/retract the valve prior to deployment and final release. Another control may be an outer shaft, which may contain a polymer sheath that functions as the valve-collapsing/expanding mechanism. Inside the outer shaft and within the sheath, there may be an internal movable shaft that is connected to the delivery device tip at the distal end of the delivery system. The shaft may be notched such that a wheel with teeth can engage and move the shaft axially when rotated in either direction (advance or retract). The prosthetic heart valve may be mounted onto this shaft and between the tip and a base. The base platform may function as a valve holding and constraining mechanism. The valve may rest on this base and can be secured in place using various mechanisms. For example, the base can have features and through-holes to allow the valve's proximal struts to be securely fastened using a suture that runs to the outside of the device at the handle on the proximal end. When the operator is satisfied with the position and orientation of the valve, the valve can be released by cutting and pulling out this suture. Alternatively, other mechanisms can be employed to secure the valve in place until final release.
The internal movable shaft may contain multi-lumens that connect manifold ports at the proximal end of the device to one or more openings at or near the distal end (tip). These lumens can be utilized for various functions such as delivery of fluids (saline, contrast, etc.) and deployment of embolic protection devices, balloons for valvuloplasty, etc.
Outside the outer shaft, a spring-loaded, donut-shaped component can be included to aid in sealing the apex of the heart or other access at the entry point by way of gentle pressure driven by the spring.
The delivery system can be manufactured from materials that are known to be biologically compatible for short-term human interaction, since this device is not a permanent implant. However, material selection should take into account the fact that this device will come into contact with a permanent implant.
The device handle can be injection molded from a bio-compatible polymer material. The elongated shaft can be polymeric or laser cut/machined surgical grade stainless steel. Internal working components can be either from a polymeric origin, stainless steel, shape-memory nitinol (nickel/titanium alloy) material, etc., depending on each component's function and performance requirements. The manifold can be an injection molded polycarbonate. The sealing donut can be made from various durometers of silicone. The device components may fit together using various means of interference fit, tabs, slots, glue, polymer heat bonds, and/or locking mechanisms to facilitate a seamless working system.
Various advantageous features of the invention are identified (to some extent recapitulating the foregoing) in the next several paragraphs.
Certain aspects of the invention relate to providing ergonomic, hand-held, easy-to-use delivery system for collapsible/expandable prosthetic heart valves. Such a delivery system may include a handle and an elongated shaft that houses the valve. The handle can incorporate controls for specific functional features within the device.
The delivery system may include valve release, retrieve, and/or reposition mechanisms.
The device may include one or more radio-opaque marker bands (e.g., at or near the distal tip) for guidance and visualization of the delivery system (especially the distal end) under fluoroscopy in the case of all-polymer construction.
The device may include precision, wheel-driven, advance/retract capabilities for precise valve positioning. Alternate mechanisms (e.g., a sliding lever) are also possible.
The device may include capabilities for fully deploying the valve but not releasing it when recapture is desired.
The device may include multi-lumen capabilities in the shaft for procedural support using ancillary devices such as guide wires, balloon catheters, embolic protection devices, fluids delivery (flushing or visualization), etc.
The valve can be secured to internal features of the delivery system using different configurations. One way is to secure the proximal end of the valve to a holder base (e.g., using sutures, mechanical interference fit features, etc.). Another way is to utilize a suture (or polymer-covered thin wire or any other appropriate means similar to this) to run from the proximal end of the device (handle) through specifically designed structures within the valve. This strand can then run through specifically designed channels in the device tip and back inside the central lumen (or other specific lumen) and end outside the device by the handle where the operator can control it. Tensioning or loosening this wire/suture will cause the valve to deploy or re-collapse. This can be used to partially deploy the valve and recapture it for repositioning or retrieval as desired.
A movable sheath, with an independent control at the handle, can function as the valve collapsing/expanding mechanism by advancing/retracting the sheath over the valve. The sheath may also maintain and protect the valve in the collapsed state. The sheath can also facilitate partial deployment and expansion of the valve, e.g., so that the operator of the apparatus can check for appropriate positioning of the valve in the patient.
The device may include features in the tip and valve holder base to control valve orientation within the delivery system so that the valve can be deployed with the correct angular orientation about its longitudinal axis, e.g., to align commissures of the prosthetic valve relative to commissures of the native valve as desired. These features can be undercuts or depressions that correspond to features on the prosthetic valve, for example.
Along with the conventional purse-string suture, a spring-loaded, silicone, molded, donut-shaped component can aid in sealing the entry port at the apex of the heart or other access into the patient's circulatory system.
The device may include the capability of opening and closing off access to any of the lumen ports at the back manifold connector.
The device tip may include features that allow the valve distal end to rest in a manner that controls the valve's collapsed diameter (e.g., to prevent damage to the stent and valve leaflets during collapse of the valve for minimally invasive delivery).
The delivery system can include a fork-like structure that can protrude and extend outside the shaft near the distal end to force open calcified native heart valve leaflets (e.g., into the sinuses of the valsalva) in preparation for valve deployment and release. Another example of an embodiment for such purposes is to deploy a structure like an umbrella. Such an umbrella design can serve two functions: (1) calcified leaflet retention, pushing such native leaflet structures out of the way in preparation for new valve deployment, and (2) embolic protection, which can be achieved by incorporating a fine mesh within the deployed ribs of the umbrella, thus capturing any emboli from the procedure. Once the procedure is completed, this umbrella can be collapsed and retracted back into the shaft, thereby safely removing from the patient all emboli and any calcified debris. An example of a structure that can be used to collapse the umbrella when desired includes a thin strand (e.g., wire or suture) attached to each of the umbrella ribs. These strands extend into the main central lumen. Pulling these strands from the proximal end causes the ribs of the umbrella to collapse.
The delivery system wheel can be centered in the handle for rotation access from both sides of the handle, or it can be offset to protrude from only one side of the device handle.
The device preferably contains seals in various areas to prevent blood from seeping through the various channels and outside the heart.
Further features of the invention, its nature and various advantages, will be more apparent from the accompanying drawings and the following detailed description.
An illustrative embodiment of prosthetic heart valve delivery apparatus 10 in accordance with the invention is shown in
Elements 20, 30, and 70 remain outside the patient at all times. Elements 40, 50, and 60 are designed for insertion into a patient's body in a low invasiveness manner to deliver a prosthetic heart valve into the patient and to deploy (implant) that prosthetic heart valve in the patient. More particularly, the prosthetic heart valve is initially contained (in a collapsed condition) in a distal portion of apparatus 10 (i.e., inside shaft 40, concentrically around shaft 50, and abutting distal tip 60). In this condition of the apparatus, shaft 40 may help to keep the valve collapsed, and distal tip 60 (which is proximally retracted) may help to keep the valve inside shaft 40. When the distal portion of the apparatus reaches the desired implant site for the valve in the patient, wheel 30 can be rotated to extend distal tip 60, a distal portion of shaft 50, and the prosthetic heart valve from the distal end of shaft 40. This allows the prosthetic heart valve to expand radially outwardly from shaft 50 to its full operating size, which also causes the valve to engage surrounding native tissue of the patient and thereby implant in the patient. The apparatus can then be withdrawn (proximally) from the patient. In particular, distal tip 60 comes out through the center of the now-expanded valve.
More details regarding the foregoing will be provided later in this specification.
It should be noted that in the
An alternative embodiment of device 10 is shown in
When the distal portion of apparatus 10 reaches the desired location in the patient (i.e., the desired location for implanting the prosthetic heart valve), distal tip 60 and some associated structure may be displaced distally from the distal end of shaft 40 as shown in
The next step is shown in
The next step is illustrated by
An example of how strands 130 may be used is as follows. The gradual proximal retraction of sleeve 120 (described in earlier paragraphs) allows heart valve 200 to gradually deploy radially outwardly. Strands 130 are relaxed or loose at this time. The gradual deployment of valve 200 may be observed by the operator of the apparatus (e.g., via x-ray, fluoroscopy, or the like). If the valve is not going in as desired, expansion of the valve can be stopped by stopping the proximal retraction of sleeve 120. Strands 130 can then be tightened by pulling proximally on their proximal portions, and at the same time sleeve 120 can be pushed in the distal direction. This combination of tightening strands 130 and pushing distally on sleeve 120 causes valve 200 to collapse back into the sleeve. The apparatus can then be repositioned to reposition valve 200 in the patient (after which the valve can be deployed again), or alternatively the valve can be completely removed from the patient with all of the surrounding instrumentation. Assuming that the valve remains in the patient, then when the operator of the apparatus is satisfied with its deployed position and condition, strands 130 can be removed (or effectively removed) by pulling on one proximal portion of each strand until the other end of that strand has been past valve 200 two times (once going in the distal direction, and then going in the proximal direction).
Strands 130 can be made of any suitably tensilely strong but laterally (transversely) flexible material. Examples include suture material, metal wire, or the like.
As was mentioned earlier in this specification, principal components of valve 200 include frame 210 (e.g., of a highly elastic metal such as nitinol) and a plurality of leaflets (e.g., three leaflets) 220 of a flexible material such as tissue that has been rendered effectively inert and otherwise made suitable for long-term, non-reactive use in a patient's body. Leaflets 220 are secured to frame 210 in such a way that the leaflets can open (to allow blood to flow through the valve from left to right as viewed in
The illustrative configuration of valve 200 that is shown in the FIGS. herein is particularly adapted for use as a prosthetic aortic valve. Details of valve 200 will therefore be described in that context. It will be understood, however, that this is only an example, and that the prosthetic valve can be alternatively configured differently in some respects to adapt it for use as a replacement for other valves in the heart or circulatory system.
Frame 210 is preferably a continuous, one-piece, annular (ring-like) structure (e.g., a structure that has been cut (using a laser) from a tube and then further processed to achieve a desired shape). Frame 210 has a “lower” (upstream or blood inflow) portion 212 that extends in a serpentine (undulating or zig-zag) fashion all the way around the valve. This portion of frame 210 may be designed for implanting in or near the patient's native valve annulus. Frame 210 also includes an “upper” (downstream or blood outflow) portion 216 that also extends in a serpentine (undulating or zig-zag) fashion all the way around the valve. This portion of frame 210 may be designed for implanting in the patient's aorta downstream from the valsalva sinus of the patient. Frame portions 212 and 216 are connected to one another by a plurality of links or struts 214 that extend between those other frame portions at locations that are spaced from one another around the valve. Struts 214 may bow or bulge radially outwardly (as shown) to follow the inner surface of lobes of the valsalva sinus.
Frame 210 may include commissure post members 218 that extend up from lower portion 212 at appropriate locations around the valve (analogous to the commissures of the patient's native heart valve). These posts 218 can form important portions of the frame structure to which leaflets 220 are attached.
Frame 210 may also include other structures 219 that extend up and incline radially out from lower portion 212 to help hold back the patient's native valve leaflets, which (to the extent left remaining in the patient) are no longer functional.
Frame 210 may also include barbs (e.g., 211) at various locations to engage (and possibly penetrate) the patient's native tissue to help hold the valve in place where deployed in the patient.
The point of making annular frame portions 212 and 216 serpentine is to facilitate annular (circumferential, radial) collapse and subsequent re-expansion of the valve. Such collapse is preferably elastic, and the subsequent re-expansion is preferably resilient.
Although not shown herein, it will be understood that valve 200 may also include other components such as one or more layers of fabric and/or tissue on various parts of the valve. Such additional layers may be for such purposes as to promote tissue in-growth, to reduce the amount of contact between frame 210 and surrounding native tissue, to prevent moving portions of leaflets 220 from contacting frame 210, etc.
Illustrative details for collar 140 are shown in
Other features of collar 140 may include recesses or sockets 144, into which extreme proximal portions (e.g., 211) of frame 210 may extend when valve 200 is in the collapsed condition. Such engagement between frame 210 and collar 140 can help ensure that valve 200 always maintains a known rotational (angular) orientation about the longitudinal axis of the apparatus. This can be helpful to ensure that rotation of apparatus 10 about its longitudinal axis produces exactly the same rotation of valve 200 about that axis. This may be important, for example, to help the operator of the apparatus position valve 200 for deployment with commissure posts 218 in a desired rotational or angular position relative to the patient's native valve commissures. As a specific example, it may be desirable for each commissure post 218 to be aligned with and inside a respective one of the patient's native valve commissures. This may necessitate rotation of apparatus 10 about its longitudinal axis, and features like 144 (with certain valve frame features received within those features 144) can help ensure that valve 200 has a known angular relationship to apparatus 10, and that this angular relationship is always maintained until the valve is deployed from the apparatus. Snug engagement between collar 140 and shaft 50 is also part of this aspect of the invention in this embodiment.
Still other possible features of collar 140 are apertures 146 for passage of above-described strands 130 through the collar.
A purpose of apparatus 300 is to capture any debris (e.g., emboli) that may be dislodged from inside the patient during deployment of prosthetic heart valve 200 and/or the expansion of fork fingers 110. Thus embolic protection apparatus 300 is typically deployed in the patient, early in the procedure, downstream from the location at which valve 200 will be deployed. For example, assuming that valve 200 is a replacement for the patient's native aortic valve, apparatus 300 may be deployed in the patient's aorta downstream from where the prosthetic valve will be employed. Apparatus 300 acts like a blood filter. It allows blood to flow through, but it captures any particles or the like that should not be allowed to remain in the patient's blood stream. After prosthetic valve 200 has been implanted, apparatus 300 is collapsed (still retaining any debris it has captured) and removed from the patient in the opposite way from which it was introduced.
In this embodiment, apparatus 300 is a structure somewhat like an umbrella. In particular, structure 300 has a central shaft 310, and a plurality of ribs or spokes 320 that are attached to a distal portion of shaft 310 and that can either collapse inwardly against (parallel to) shaft 310 or that can incline radially outwardly from shaft 310. Another element of structure 300 is a flexible, emboli-catching web or mesh (blood filter) 330 attached to ribs 320. Still other components of structure 300 are tethers 340 (shown only in
Before deploying valve 200, apparatus 300 may be introduced into the patient in a collapsed condition via proximal connector 70, a lumen through tube 100, and distal tip aperture 62. When apparatus 300 is at the desired location in the patient's circulatory system downstream from where valve 200 is to be implanted, the proximally directed tension on proximal portions of strands 340 may be released. This allows ribs 320 to resiliently deflect outwardly into an array somewhat like the ribs or spokes of an open umbrella. Ribs 320 carry out with them, and thus also open, blood filter web 330. These structures (i.e., 320 and 330) preferably bear against an annular portion of the inner surface of a blood vessel (e.g., the aorta) downstream from where valve 200 will be implanted in the patient.
After valve 200 has been deployed, embolic protection apparatus 300 may be collapsed again by pulling proximally on tethers 340. This causes ribs 320 to again become parallel to and against central shaft 310. Blood filter 330 (with any captured debris) is thereby also collapsed against central shaft 310. This allows apparatus 300 to be pulled back into device 10 via the aperture 62 in distal tip 60.
Note that apparatus 300 may include ribs 320 that extend proximally back from blood filter 330 per se. These rib extensions may serve the additional function of pushing back (radially outwardly) the leaflets of the patient's native heart valve prior to deployment of prosthetic valve 200.
After apparatus 300 (with above-mentioned, optional, proximal, rib extensions) has been deployed, the distal portion of device 10 may be moved distally closer to apparatus 300. The distal portion of device 10 may then be opened and valve 200 may be deployed as shown in
It will be understood that the foregoing is only illustrative of the principles of the invention and that various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention. For example, the shapes and sizes of various components can be different from the shapes and sizes employed in the illustrative embodiments shown herein. As another example, the lateral stiffness of shaft 40 and/or other longitudinal elements within shaft 40 can be selected to render the apparatus suitable for different possible uses and/or preferences. Thus in some embodiments it may be desirable for the shaft portion of the apparatus to be relatively stiff or even rigid or substantially rigid (i.e., not flexible or bendable transverse to or laterally of its longitudinal axis). On the other hand, in other embodiments it may be desirable for the shaft portion of the apparatus (or certain parts of the shaft portion) to be more laterally flexible.
1. Apparatus for delivering a prosthetic heart valve into a patient comprising:
- a hollow, tubular, longitudinal, outer shaft extending from a proximal portion of the apparatus to a distal portion of the apparatus;
- a longitudinal inner shaft disposed inside the outer shaft and substantially longitudinally aligned therewith, the inner shaft being longitudinally movable relative to the outer shaft;
- a tip structure mounted on a distal portion of the inner shaft for substantially closing a distal end of the outer shaft when the inner shaft is pulled proximally back relative to the outer shaft; and
- a prosthetic heart valve disposed around the inner shaft proximal of the tip structure and inside a distal portion of the outer shaft, the heart valve being releasable from the apparatus when the distal tip is moved distally away from the distal end of the outer shaft and the heart valve is shifted distally beyond the distal end of the outer shaft.
2. The apparatus defined in claim 1 further comprising:
- a handle structure attached to a proximal portion of the outer shaft.
3. The apparatus defined in claim 2 further comprising:
- a toroidal structure disposed concentrically around the outer shaft distally of the handle structure, the toroidal structure being movable along a length of the outer shaft; and
- a resilient structure for resiliently urging the toroidal structure to move in a distal direction along the shaft.
4. The apparatus defined in claim 3 wherein the toroidal structure has blood-sealing engagement with an outer surface of the outer shaft.
5. The apparatus defined in claim 1 wherein the prosthetic valve is resiliently biased to expand radially outwardly when released from confinement to a collapsed size that fits within the outer shaft.
6. The apparatus defined in claim 1 further comprising:
- a native leaflet displacing structure deployable from a distal end of the outer shaft when the tip structure moves distally away from the distal end of the outer shaft, the native leaflet displacing structure being resiliently biased to enlarge radially outwardly when deployed from the distal end of the outer shaft.
7. The apparatus defined in claim 2 further comprising:
- an actuator structure mounted in the handle structure for moving the inner shaft longitudinally relative to the outer shaft.
8. The apparatus defined in claim 2 further comprising:
- a connector structure mounted on the handle structure, the connector structure including a lumen that connects to a lumen structure through the inner shaft and the tip structure.
9. The apparatus defined in claim 1 further comprising:
- a collar structure around the inner shaft and spaced in the proximal direction from the tip structure, the prosthetic valve being positioned between the collar structure and the tip structure.
10. The apparatus defined in claim 9 wherein a proximal end portion of the prosthetic valve bears on the collar structure.
11. The apparatus defined in claim 10 further comprising:
- a plurality of strands for releasably securing the prosthetic valve to the collar structure.
12. The apparatus defined in claim 11
- wherein each of the strands loops through a proximal portion of the prosthetic valve and then extends proximally from the prosthetic valve inside the outer shaft.
13. The apparatus defined in claim 11
- wherein each of the strands extends through the collar structure, around the prosthetic valve, to the tip structure.
14. The apparatus defined in claim 13
- wherein each of the strands loops through the tip structure, and then back to a proximal portion of the apparatus.
15. The apparatus defined in claim 1 further comprising:
- a sheath structure around the prosthetic valve inside the outer shaft, the sheath structure being longitudinally shiftable relative to the outer shaft.
16. The apparatus defined in claim 15
- wherein the sheath structure is additionally longitudinally shiftable relative to the inner shaft.
17. The apparatus defined in claim 16
- wherein the sheath structure is additionally longitudinally shiftable to expose the prosthetic valve for deployment in the patient.
18. The apparatus defined in claim 17
- wherein, after the sheath structure has been shifted to expose the prosthetic valve, the sheath structure is further shiftable to again enclose the prosthetic valve.
19. The apparatus defined in claim 8 further comprising:
- embolic protection structure selectively deployable through the lumen structure distally beyond the tip structure.
20. The apparatus defined in claim 19
- wherein the embolic protection structure is resiliently biased to expand radially outwardly when deployed distally beyond the tip structure.
21. The apparatus defined in claim 19
- wherein the embolic protection structure deploys to form a blood filter.
22. The apparatus defined in claim 20
- wherein the embolic protection structure is collapsible to re-enter the lumen structure.
23. The apparatus defined in claim 19
- wherein the embolic protection structure includes elements for pushing leaflets of a patient's native heart valve radially outwardly.
24. The apparatus defined in claim 1 wherein the apparatus is configured for delivery of the prosthetic valve via the apex of the patient's heart.
25. The apparatus defined in claim 1 wherein at least one of the shafts is substantially laterally rigid.
26. The apparatus defined in claim 1 wherein both of said shafts are laterally flexible along at least a portion of their lengths.
27. The apparatus defined in claim 1 further comprising:
- embolic protection structure selectively deployable distally from the tip structure.